This document discusses the organization and properties of elements in the periodic table. It describes how elements are organized into periods and groups based on their electron configuration. Elements within the same group have similar chemical properties because they have the same number of valence electrons. It also distinguishes between metals, nonmetals, and metalloids, and discusses some representative properties and common elements in various groups of the periodic table.

3. Periods and Groups
Periods
 Rows of elements are called periods.
 The period number of an element
signifies the highest unexcited energy
level for an electron in that element.
 The number of elements in a period
increases as you move down the
periodic table because there are more
sublevels per level as the energy level of
the atom increases

4. Groups
 Columns of elements help define element
groups.
 Groups of elements have the same outer
electron arrangement.
 The outer electrons are called valence
electrons.
 Because they have the same number of
valence electrons, elements in a group share
similar chemical properties.

6. Representative vs. Transition
Elements
The group A elements are
called the representative
elements.
The group B elements are
the nonrepresentative
elements.

7. Representative Elements

8. Metals exhibit the following properties:
Luster – shiny.
Ductile – drawn into wires
Conductors of heat and electricity
Malleable – hammered into sheets.

9. Group 1: Alkali Metals
 The alkali metals are located in Group IA
(first column) of the periodic table.
 Alkali metals form salts and many other
compounds.
 These elements are less dense than
other metals, form ions with a +1
charge, and have the largest atom sizes
of elements in their periods.
 The alkali metals are highly reactive.

11. Group 2: Alkaline Earth
Metals
 The alkaline earths are located in Group
IIA (second column) of the periodic
table.
 Calcium and magnesium are examples
of alkaline earths.
 These metals form many compounds.
They have ions with a +2 charge.
 Their atoms are smaller than those of
the alkali metals.

13. Groups 3-12: Transition
 The transition elements are located in
groups IB to VIIIB.
 These elements are very hard, with high
melting points and boiling points.
 The transition metals are good electrical
conductors and are very malleable.
 They form positively charged ions.

15. Metal Triads
 The iron triad consists of iron, cobalt,
and nickel.
 Just under iron, cobalt, and nickel is the
palladium triad of ruthenium, rhodium,
and palladium,
 While under them is the platinum triad of
osmium, iridium, and platinum.

17. Lanthanides
 The lanthanides are silvery metals that
tarnish easily.
 They are relatively soft metals, with high
melting and boiling points.
 The lanthanides react to form many
different compounds.
 These elements are used in lamps,
magnets, lasers, and to improve the
properties of other metals.

19. Actinides
 The actinides are in the row below the
lanthanides.
 Their atomic numbers follow actinium.
All of the actinides are radioactive, with
positively charged ions.
 They are reactive metals that form
compounds with most nonmetals.
 The actinides are used in medicines and
nuclear devices.

21. Non-metals are Dull, Brittle and
Nonconductors- insulators

22. Hydrogen has a single positive charge, like the
alkali metals, but at room temperature, it is a gas
that doesn't act like a metal. Therefore, hydrogen
usually is labeled as a nonmetal.

23. Metalloids or Semimetals
have Properties of both metals and non
metals are Semiconductors

24. Group 17: Halogens
 The halogens are located in Group VIIA
of the periodic table. You find these
elements in bleaches, disinfectants, and
salts.
 These nonmetals form ions with a -1
charge. The physical properties of the
halogens vary. The halogens are highly
reactive.

26. Group 18: Noble Gases
 The noble gases are located in Group
VIII of the periodic table.
 These elements are used to make
lighted signs, refrigerants, and lasers.
 The noble gases are not reactive.
 This is because they have little
tendency to gain or lose electrons.

30. Atomic Radius
 The one half of the distance between
the nuclei of two atoms of the same
elements when the atoms are joined.

32. Ionic Size
 The size of an ion is governed not only
by its electronic structure but also by
its charge.

33. Ionization energy
 Ionization energy is the minimum
energy (in kJ/mol) required to remove an
electron from a gaseous atom in its
ground state.
 1st ionization energy decreases down
a group.
 1st ionization energy increases
across a period.

35. Electron affinity
 the negative of the energy change that
occurs when an electron is accepted by
an atom in a gaseous state to form an
anion.

37. Electronegativity
 The ability of an atom to attract toward
itself the electrons in a chemical bond.
 Elements with high electronegativity
have a greater tendency to attract
electrons than do elements with low
electronegativity

39. Melting
 When a substance melts, some of the
attractive forces holding the particles
together are broken or loosened so that
the particles can move freely around
each other but are still close together.
The stronger these forces are, the more
energy is needed to overcome them and
the higher the melting temperature.

41. Boiling
 When a substance boils, most of the
remaining attractive forces are broken
so the particles can move freely and far
apart. The stronger the attractive forces
are, the more energy is needed to
overcome them and the higher the
boiling temperature